This invention relates to a power driven hair clipper.
A power driven hair clipper of the type initially referred to is known from U.S. Pat. No. 1,997,096, having a cutter head mounted for pivotal motion into corresponding positions for shaving and trimming, comprising a supporting element mounted for controlled pivotal motion along a curved track, a comb plate with only one row of teeth, and a cutter blade held in engagement with the comb plate by means of a resilient tension plate resting on the supporting element. An actuating element extending from the upper end of the casing transmits the driving motion to the cutter blade. A friction element acted upon by a spring element is arranged in the supporting element in such a way that it is urged against the upper surface of the hair clipper""s casing in order to hold the cutter head in any given pivot position by frictional pressure engagement. For the cutter head to be displaceable from its position of adjustment, the predetermined frictional force has to be overcome. This can lead during clipper operation to undesirable changes of position, especially since frictional forces tend to decrease in the course of using the hair clipper.
A power driven hair clipper of the type initially referred to is further known from U.S. Pat. No. 2,741,026. The cutting head, formed by an outer blade and an inner cutting blade driven to oscillate, is rigidly fastened to the yoke arms of the casing head constructed in a U-shaped configuration. The arcuate shape of the outer blade with its two rows of cutting teeth permits the hair clipper and the outer blade fastened thereto to execute a restricted pivot movement of 9xc2x0, while the relatively large distance of the cutting head""s row of teeth used at a time to the biggest diameter of the hair clipper""s casing is intended to enable both rows of teeth to be used for trimming purposes.
From GB-A-2 294 230 there is known a power driven hair clipper with a cutter head mounted for pivotal motion in all directions, whose pivotability is assured by a ball and socket connection between the housing and the cutter head. The cutter head, comprised of a supporting element and a housing cover member, includes a pair of blades, each equipped with two rows of cutting teeth extending parallel to each other but arranged in the cutter head in such a way that only one of the cooperating rows of cutting teeth on the pair of blades projects out of the cutter head housing. For the second row of cutting teeth to be brought into use, the cutter head has to be opened to enable the pair of blades to be turned through 180xc2x0 inside the cutter head.
From PCT-WO 98/47673 there is known a clipper head for a power driven hair clipper, comprising a supporting element, a clipper comb fastened thereto, and a clipper blade urged into engagement with the clipper comb via a driving element arranged to oscillate, under the action of a spring element bearing against the supporting element. A coupling element for transmitting the movement from the drive mechanism of the hair clipper to the clipper blade is provided on the driving element. To reduce the friction between the clipper comb and the clipper blade provision is made between the ends of the clipper comb and the clipper blade on the side remote from the row of cutting teeth for a component made of a material displaying reduced friction properties. For cleaning and replacement purposes, the supporting element of the clipper head is attachable to the housing by means of a clip connection.
It is an object of the present invention to improve a power driven hair clipper of the type initially referred to in respect of its function and handling.
According to the invention this object is accomplished with a power driven hair clipper of the type initially referred to in that the clipper comb is in cooperating relationship with two clipper blades, each being adapted to be coupled with a drive member of the drive mechanism according to the pivot position of the clipper head relative to the housing. This invention has numerous advantages. One advantage is that, using a pivotal motion, the clipper head with its two rows of cutting teeth can be brought into an optimal cutting position relative to a skin surface and that, in such a pivot position, only one of the two clipper blades associated with the clipper comb is coupled with the drive member of an electric drive mechanism provided in the housing. This results in a reduction of power consumption because only that clipper blade intended to be used at any one time is driven to cooperate with the clipper comb. The cooperative relationship of two clipper blades with one clipper comb advantageously enables the rows of teeth of the clipper comb and the rows of teeth of the two clipper blades to be differently constructed, for example by having the width of one row of cutting teeth significantly smaller than the width of the other row of cutting teeth. Furthermore, it is also possible for the contour of one row of cutting teeth to be straight, for example, as opposed to an arcuate contour of the second row of cutting teeth opposite. Different constructions of this type enlarge the hair clipper""s scope of use.
According to a preferred embodiment of the invention the clipper head is securable to a supporting element mounted on the housing for pivotal motion about the pivot axis. This arrangement guarantees that the clipper head can be easily and quickly coupled to and uncoupled from the pivotable supporting element of the hair clipper, thus making it possible to exchange clipper heads, to clean detached clipper heads and to replace clipper heads.
In a further aspect of the invention the supporting element is constructed as a housing shell. The housing shell advantageously surrounds the components of the clipper head fastened to the clipper comb, providing protection from damage.
One embodiment of the invention is characterized in that the housing shell is pivotally mounted on two opposing side walls of the housing. According to the invention one end of the housing is preferably constructed in a U-shaped yoke configuration, with the housing shell being pivotally mounted on the yoke arms of the housing by means of pivot bearings.
According to a preferred embodiment of the invention the it pivot bearings are formed by cooperating conical bearing elements. The cooperation of the conical bearing elements forming a conical bearing is promoted by having a bearing pin pass through the conical bearing. Optimal cooperation between the conical bearing elements and the bearing pin is guaranteed in that the bearing pin is movable against the pressure of at least one spring element.
According to yet another embodiment of the invention the clipper head is releasably attached to the supporting element by means of a locking device. Actuation of the locking device en25 sures easy and fast removal of the clipper head from the supporting element.
In a further embodiment of the invention a chassis is fastened to the clipper comb with its two rows of cutting teeth. In a further aspect of this embodiment provision is made for the chassis to act as the carrier of components of the locking device. In yet another aspect of this embodiment of the invention the chassis is provided with at least one locking device having a latching element movable against the pressure of a spring element. Preferably at least one latching element for the locking device is arranged on the supporting element.
A preferred embodiment of the invention is characterized in that the pivot range of the clipper head is limitable by stops. Preferably these stops are formed by wall elements.
According to a further advantageous embodiment of the invention the pivot range of the clipper head is locatable by means of a detent device. The detent device is preferably formed by at least one notch and one detent element adapted to be acted upon by a spring element.
According to yet another embodiment of the invention the spring element and the detent element are provided in the housing, and the notch is provided on an outer wall of the supporting element.
In a preferred embodiment the clipper head with the housing shell of the supporting element is pivotally mounted inside a housing head shell of the housing on the wall of the housing head shell. In a further aspect of this embodiment the directions of extension of the wall of the housing on either side of the pivot bearings are each aligned parallel to a maximal pivot angle of the clipper head. According to one embodiment of the invention the pivot angles of the clipper head are constructed to be of equal size. According to another embodiment of the invention the pivot angles of the clipper head are constructed to be of different size.
According to yet another embodiment of the invention the chassis is arranged on a foil resting on the clipper comb. According to a particularly advantageous embodiment of the invention the end of the clipper blade on the side remote from a row of cutting teeth is slidably held on the foil. To reduce the friction of the clipper blade on the foil provision is made in one embodiment of the invention for the foil to have a perforation. According to the invention the friction is further reduced by using the perforation as a receptacle for a lubricant. According to an embodiment of the invention the perforation is formed by holes. In another embodiment of the invention the perforation is formed by flanges.
An embodiment of the present invention will be described in the following with reference to the accompanying drawings.